WireGaugeCalc Free calculator · NEC cited · works offline
Load Test Calculator
Load test calculator is fast with WireGaugeCalc, since you enter each load and read the total demand in amps at once.
It adds your connected loads, applies the demand factors you choose, and converts watts to amps using the circuit voltage.
So you get a clear total before you size the wire or the breaker.
Open the calculatorEnter any two values and read the rest.
Ohm’s law: V = I × R and P = V × I. Field aid only, verify against the current NEC and your local authority having jurisdiction.
Total Your Connected Load In Amps
You enter each load in watts or amps, and the calculator sums them so you see the full circuit demand.
It uses Ohm's law and the voltage you pick to turn power into current, since amps drive your wire and breaker choice.
The result shows the running total, so you know how close you are to the circuit limit.
What The Calculator Checks
Each entry feeds into a clear total you can act on:
- Sums watts or amps across every load you add
- Converts watts to amps using 120V, 240V, or your value
- Applies the demand factor you select
- Shows the running total against the circuit rating
- Flags when the load nears the breaker size
One app for every NEC calculation
WireGaugeCalc keeps the calculations you reach for most in one place:
- Voltage drop and wire sizing for any run
- Conduit fill for EMT, PVC, and RMC
- Box fill and junction box sizing
- Ampacity and temperature derating
- Motor circuit and load calculations
- Conduit bend offsets and saddles
Built for the field, works offline
The whole app runs on your phone, so it keeps working in a basement, an attic, or a job site with no signal.
There is no account to create and nothing to load. Open it, run the number, and get back to work.
- No signup and no signal needed
- Answers in a tap, not a spreadsheet
- Same tool on phone, tablet, and desktop
Every result cites the NEC article
Each answer shows the table or formula it came from, so you can check the method and learn the code as you go.
That makes the app useful on the job and during exam prep, since the reasoning is right next to the number.
Switch the code year your job runs on
Jurisdictions adopt the NEC at different times, so you can match the calculation to the code in force:
- NEC 2017, 2020, and 2023 tables
- Copper and aluminum conductors
- 60, 75, and 90 degree C terminations
- Single-phase and three-phase systems
Run the number, then get back to work
Stop flipping through a paper book or hopping between calculator sites. Enter your values, read the code-cited answer, and move on. Free to use, no signup.
Open the calculatorFrequently asked questions
How do I convert a load in watts to amps?
Divide the watts by the circuit voltage, so 1800 watts on a 120V circuit is 15 amps. The calculator does this for each load automatically.
Should I add up loads at the full nameplate value?
Start with the nameplate values, then apply the demand factor the code allows for that load type. Verify the demand factors against the current NEC and your local authority having jurisdiction before you finalize the design.
Is WireGaugeCalc free to use?
Yes. Every calculator is free to run with no signup. A paid tier adds saved projects, PDF reports, and extra code years, but the core math stays free.
Does it work without internet?
Yes. The app runs on your device, so it keeps working with no signal on a job site, in a basement, or in an attic.
Are the results code accurate?
Results follow published NEC tables and standard formulas, and each answer shows the article it came from. It is a field aid, not a stamp of approval, so verify against the current code and your local authority before you wire anything.
Which NEC code year does it use?
You can switch between NEC 2017, 2020, and 2023, since jurisdictions adopt the code at different times. Pick the year your job runs on.